YUP simple logo button you can click on to see pro… this on places in the CP where it makes sense so where pro functions doing thier yob to have advances above gpl.
I know this is probably tomuch work and recources , but a in use not in use / active not active day / hourly and then deduct this from payed upfront account if reached 10 or 20 whatever.
Kind of how several cloudproviders , openstack and container… handle…
I know that this is probaby to much… so sorry sharing this then 